Yes, the iPhone 12 global version will work in the United States. The iPhone 12 is designed to be a versatile and global device, supporting various network bands and technologies that are used worldwide, including those used in the United States.

The iPhone 12 global version is equipped with the necessary hardware and software to operate on both GSM and CDMA networks, which are the two primary network technologies used in the United States. GSM networks are utilized by major carriers like AT&T and T-Mobile, while CDMA networks are used by carriers like Verizon and Sprint (now part of T-Mobile).

The iPhone 12 supports a wide range of network bands, including the ones commonly used in the United States, such as LTE bands 1, 2, 3, 4, 5, 7, 8, 12, 13, 14, 17, 18, 19, 20, 25, 26, 28, 29, 30, 32, 34, 38, 39, 40, 41, 42, 46, 48, 66, 71, and 77. These bands cover the necessary frequency ranges for optimal network compatibility in the United States, ensuring that the iPhone 12 can connect to and function on major carriers' networks.

Additionally, the iPhone 12 supports 5G connectivity, including both sub-6 GHz and mmWave technologies. This allows the device to take advantage of the growing 5G networks in the United States, providing faster download and upload speeds where available.

It's worth noting that to ensure compatibility and optimal network performance, it's important to purchase an unlocked iPhone 12 or one specifically designated as being compatible with the desired carrier in the United States. Carrier-specific models are often sold directly by the carriers themselves or through authorized retailers.

When obtaining an unlocked iPhone 12 global version or carrier-specific model, it's essential to insert a SIM card from a compatible carrier and activate the device with that carrier. This will allow the iPhone 12 to access the carrier's network services, including voice calls, text messaging, and data connectivity.

In summary, the iPhone 12 global version is designed to work in the United States, supporting both GSM and CDMA networks and a wide range of network bands. As long as you have a compatible, unlocked device or a carrier-specific model, and you insert a SIM card from a supported carrier, you should have no issues using the iPhone 12 in the United States and enjoying its full range of features and functionalities.